Process of making glue and gelatin.



i atented September 8, 1903 PATENT FFIGE.

HERMANN WEISS, OF HILOHENBAQH, GERMANY.

PROCESS OF MAKING GLUE AND GELATIN.

SPECIFICATION forming part of Letters Patent No. 738,709, dated September 8, 1903.

Application filed November 21, 1902. Serial No. 13233 2. (N specimens.)

1'0 aZZ, whom it may concern: 7 r

' Be it known that I, HERMANN WVEISS, asubject of the German Emperor, residing at I-Iilchenba ch, Westphalia, Germany, have invented certain'new and useful Improvements in the Manufacture of Glue and Gelatin, of which the following is a specification. In the In anufacture of glue and gelatin from skin's or leather according to known processes thematerials used are principally the head parts removed in the treatment of the skins in the tanneries, the grain layer removed in the preparation of chamois-dressed leather, and generally all small cuttings and waste which are in suitable condition for being made into glue; but tanned leatherwhether barktanned, chamoisdressed, or chrome-tanned is unsuitable for the manufacture of glue, because the substances of the skin which yield the glue have been changed by the tanning materials and cannot be made into glue.

Such leather is also unsuitable for the manufacture of gelatina The-utilization of the waste of such leather is therefore almost ontirely confined to the manufacture of manure. This invention has for its object to render such leather or leather waste suitable for manufacture into glue or gelatin by a suitsolution is prepared, has been found the most suitable. The waste may be stirred, if desired. The waste is then removed from the acid solution, thoroughly washed, and treated with any suitable alkali, preferably milk of lime, for therpurpose of removing any remaining acid. After separation of the milk of limeand repeated washing with water any remaining traces of the lime are removed by treatment with acid, particularly hydrochlo- .ric acid, and the acid is then neutralized by This invention is of great economical advantage, because a new material is found for the manufacture of glue and gelatin and also because the cost of the process may be partly covered by the preparation of chrome-salts from the chrome oxid dissolved by the sulfuric acid. a

, In the case of chamois-dressed or barktanned leather or leather tanned with any other vegetable tanning substance, the process'is modified. Instead of the first treatment with acid the waste is treated with alkali, and the subsequent treatment will of course correspond.

What I claim, and desire to secure by Letters Patent of the United States, is-

1.7 A process for treating leather waste for manufacture of glue and gelatin, consisting in immersing the leather in an acid solution, then washingit and treating it with an alkali, separating the alkali and again washing the leather, removing all traces of the alkali by further treatment with acid, and then neutralizing the acid with solutions of suitable alkalies, again washing the leather and treating it in the known manner.

2. A process for treating leather and leather waste for manufacture of glue and gelatin, consisting in treating the leather with'an alkali, then separating the alkali and again washing the leather, removing all traces of alkali by treatment with acid, and then neutralizing the acid with solutions of suitable alkalies, again washing the leather and treating it in the known manner.

In testimony whereof I have hereunto set my hand in the presence of two witnesses.

HERMANN WEISS. 

